The present invention relates to a fastening device for joining two plates together and more specifically relates to a fastening device for joining an upper box and a lower box together, the boxes being intended for use in containing large equipment, heavy equipment and the like.
As FIG. 8 shows, packing of large or heavy equipment such as a television receiver, a display device, a copy machine and the like is generally performed by using an upper box 1 and a lower box 2, both of which are made of a corrugated cardboard and the like, and joining the upper box 1 and lower box 2 together in order to facilitate a packing operation and an unpacking operation as well. As a means for joining the two boxes together, a band 3 is used.
However, the packing system of this type has such drawbacks as loosening and sometimes tearing off of the band 3 during transportation. As a remedy for these drawbacks, a fastening device for packing as disclosed in the Japanese Unexamined Patent Publication TOKUKO-SHOW-56-28778 and the like has been in use.
As FIG. 9 shows, a fastening device 4 is pressed into a hole 5 for fastening that is provided as a common hole on the upper box 1 and lower box 2, thereby joining the upper box 1 and lower box 2 together. Further, this fastening device 4 is serving as a grip for holding the packing box.
Next, a detailed description is given to the fastening device 4. As FIG. 10 and FIG. 11 show, the fastening device 4 comprises a cylindrical shell 7 with dose to a square in cross section, a flange 6 formed on the edge of one opening of the cylindrical shell 7 by extending outward, a pair of hooks 8, each of which has an L-letter like shape in cross section and is linked, respectively, via a hinge 7a to one of the two sides that are opposing to each other and located on the other opening of the cylindrical shell 7 and a tab 9 formed on the upper surface of one of the pair of hooks 8. All the parts of the fastening device 4 are molded in one piece to realize a sing-piece construction by the use of a polypropylene material which shows elasticity to a degree.
As FIG. 12 shows, the pair of hooks 8 and the cylindrical shell 7 are inserted in a hole 5 for fastening that is formed as the common hole on the upper box 1 and lower box 2. Then, as FIG. 13 shows, the tab 9 is pushed upward, thereby having the pair of hooks 8 opened outward. Each respective hook 8 is opened outward by 90xc2x0 from the original upright position thereof, thereby having part of each respective hook 8 brought into contact with the perimeter of the hole 5 for fastening inside of the lower box 2 and at the same time having the remaining part of each respective hook 8 brought into contact with the inner side of the lower box 2. On the other hand, the flange 6 is made to contact the perimeter of the hole 5 for fastening outside of the upper box 1. Accordingly, the fastening device 4 is disposed in the holes 5 for fastening of the upper box 1 and lower box 2 as if the peripheries of the common hole 5 for fastening are sandwiched between the foregoing hook 8 and flange 6. Further, the tab 9 formed on the upper surface of one of the pair of hooks 8 is turned by 90xc2x0, thereby getting inside of the cylindrical shell 7. The tip end of the tab 9 is made to engage with a retainer 8a provided on the opposing hook 8. Thus, the pair of hooks 8 are fixed in a state of being opened outward.
However, the thickness of the upper box 1 and lower box 2 usually changes according to the kind or weight of the equipment to be packed. Since the prior art fastening device as described above has a fixed predetermined distance between the pair of hooks 8 opened outward and the flange 6, it has been having a problem of inability to cope with the situation where the packing box has a thickness that is different from the one, to which the fastening device in question is designed. Therefore, for use with a variety of packing boxes having a thickness different from one another, a variety of fastening devices with the sandwiching distance between a pair of hooks and a flange made different from one another have to be prepared, resulting in an adverse effect on the economic aspect involved therewith.
A fastening device and a fasting method of the present invention comprise a shell with an opening extending over the entire length of the shell, a gripping member formed on the periphery of the cylindrical shell by extending outward, and a pair of hooks linked with the tip end of the cylindrical shell via hinges.
The pair of hooks is placed in a hole for fastening of each of a first plate and a second plate. Then, each of the pair of hooks are opened outward to bring holding members thereof into contact with the bottom surface of the plate situated on the back side, and at the same time, the pair of hooks are engaged with each other firmly. At this time, the gripping member is in contact with the front surface of the plate situated on the front side. Accordingly, the two plates are sandwiched on both outer surfaces thereof at each respective rim of the hole for fastening between the pair of hooks and the gripping member. Furthermore, the fastening device is structured so as to make the position of engagement between the pair of hooks changeable, thereby allowing the angle of each respective hook against the cylindrical shell to change and allowing consequently the sandwiching distance between the gripping member and the pair of hooks to change.
A particularly preferred embodiment of the present invention is the case where the foregoing first plate and second plate are an upper box and a lower box, respectively, to be joined together for building a packing box.
According to the structure as described above, the sandwiching distance between the pair of hooks and the gripping member is made changeable. Therefore, even when the first plate (or the upper box) and the second plate (or the lower box) constituting a packing box have a difference in thickness therebetween, the fastening device prepared as above can join the first plate (the upper box) and the second plate (or lower box) together readily and firmly.